Regarding conventional sealing materials, Japanese Patent Laying-Open No. 2006-220229 (PTD 1) for example discloses a sealing material for a dovetail groove. This sealing material is excellent in ease of installation in the dovetail groove, has a high resistance to dropping, can produce a sufficient sealing strength under a low load even when the size is increased, and aims to prevent generation of particles due to metal touch.
The sealing material for a dovetail groove disclosed in PTD 1 is a sealing material in a closed annular shape, and the sealing material is installed at a location where one member in which a dovetail groove in a closed annular shape is formed and the other member are to be sealed together. The sealing material includes, as its constituent parts, a sealing material main body installed in the dovetail groove and an obliquely extending lip portion provided on an exterior surface of the sealing material main body extending outward from the dovetail grove.